Top Senate Republican Mitch McConnell says flatly that his party won't permit a vote on any Supreme Court nominee submitted by President Barack Obama but will "revisit the matter" after the presidential election in November.

In what would be a nightmare scenario for the GOP, presidential hopeful Ben Carson threatened Friday to leave the Republican Party amid reports of deepening concerns from GOP officials about the splintered 2016 electorate.

Senate Republican leader Mitch McConnell has set up a showdown vote for Thursday on a bill financing government agencies through Dec. 11 but also blocking Planned Parenthood's federal funds for a year.